Agency 9 min read

How to Keep Client Campaigns Running When Your Sending Infra Breaks

When client campaign infrastructure fails, you have two problems: fixing the technical issue and keeping the campaign running. Here's how to manage both simultaneously.

Deliverability failures during an active client campaign are an agency's worst situation. You're managing technical triage and client communication at the same time, with revenue at risk. Here's how to handle it without losing the client or the campaign.

First: triage before you communicate

Before telling the client anything, spend 30 minutes running diagnostics. Nothing is worse than telling a client "your inboxes are burned" only to discover 20 minutes later it was a broken DKIM record that took 5 minutes to fix. Know what you're dealing with before escalating.

Run the diagnostic stack in parallel:

This takes about 10 minutes. Classify the issue: technical (fixable fast) or reputation (needs time or replacement).

Scenario A: Technical issue

If auth is broken, a record is missing, or the tracking domain is misconfigured — fix it before pausing the campaign. A technical fix often resolves the placement issue within hours. Retest before resuming sends.

Scenario B: Reputation damage

If it's reputation damage — blacklisted, spam complaints, gradual decline — you have a harder decision. The options are:

  1. Pause the campaign while the domain recovers (weeks)
  2. Continue on damaged infrastructure and accept lower placement (not recommended)
  3. Move the campaign to backup infrastructure and recover the damaged domain in parallel

Option 3 is the professional approach. It requires having backup infrastructure available — which is why every agency should maintain a spare pool of pre-warmed inboxes.

The backup infrastructure model

Agencies that never lose campaigns have backup capacity ready before they need it. The standard approach:

  • Maintain 20–30% more inbox capacity than current campaigns require
  • Keep backup domains pre-warmed and not actively sending
  • When primary inboxes fail, migrate the campaign to backup inboxes within hours
  • Begin recovery of damaged inboxes in background

The cost of maintaining backup capacity is significantly less than the cost of losing a client campaign. Use the infrastructure calculator to determine how much backup capacity your campaign portfolio needs.

Client communication framework

Be honest, be technical, and have a solution ready before you call.

What not to say: "Your inboxes got burned." This is vague, alarming, and makes it sound like permanent damage.

What to say: "We identified a deliverability issue affecting [X] of your sending accounts. We've diagnosed the root cause as [technical issue / reputation damage]. We're moving the campaign to backup infrastructure now so sends can continue, and we're working on recovering the affected accounts in parallel. I'll send you a technical summary today and an update in 48 hours."

Running campaigns on backup infrastructure

When migrating to backup inboxes mid-campaign:

  • Exclude any prospects who already received emails from the damaged inboxes
  • Maintain the same sending limits on the new inboxes (don't spike volume)
  • Run a placement test on the backup inboxes before sending any campaign emails
  • Monitor open rates and bounce rates closely for the first 48 hours

Agencies that rely on WarmInboxes for backup capacity can migrate campaigns within hours because the inboxes are already warmed and ready to send. Without pre-warmed backup infrastructure, recovery takes weeks — which is almost never acceptable for active client campaigns.

Run the checks first

Before replacing anything, run a free inbox placement test. You might find the issue is DNS, not the domain — and save yourself a week of unnecessary work.

Free inbox placement test Check burn score

More guides

The Cold Email Disaster Recovery SOP Every Agency Should HaveHow Cold Email Agencies Should Build Backup Infrastructure Before Disaster HitsThe Real Cost of Burned Inboxes for Cold Email Agencies